The present invention relates to methods and compositions for the diagnosis, prevention and treatment of tumor progression in mammals, for example, humans. The different types of tumors may include, but are not limited to, human melanomas, breast, gastrointestinal tumors such as esophageal, stomach, duodenal, colon, colorectal and rectal cancers, prostate, bladder, testicular, ovarian, uterine, cervical, brain, lung, bronchial, larynx, pharynx, liver, pancreatic, thyroid, bone, various types of skin cancers and neoplastic conditions such as leukemias and lymphomas. Specifically, genes which are differentially expressed in tumor cells relative to normal cells and/or relative to tumor cells at a different stage of tumor progression are identified. For example, genes are identified which are differentially expressed in benign (e.g., non-malignant) tumor cells relative to malignant tumor cells exhibiting a high metastatic potential. Genes are also identified via the ability of their gene products to interact with gene products involved in the progression to and/or aggressiveness of neoplastic tumor disease states. The genes identified can be used diagnostically or as targets for therapeutic intervention. In this regard, the present invention provides methods for the identification of compounds useful in the diagnosis, prevention and therapeutic treatment of tumor progression, including, for example, metastatic neoplastic disorders. The present invention also provides methods for the identification of compounds useful in the diagnosis, prevention and therapeutic treatment of tumor progression, including, for example, pre-neoplastic and/or benign states. Additionally, methods are provided for the diagnostic evaluation and prognosis of conditions involving tumor progression, for the identification of subjects exhibiting a predisposition to such conditions, for monitoring patients undergoing clinical evaluation for the prevention and treatment of tumor progression disorders, and for monitoring the efficacy of compounds used in clinical trials.
Cancer is the second leading cause of death in the United States, after heart disease (Boring, C. C. et al., 1993, CA Cancer J. Clin. 43:7), and develops in one in three Americans, and one of every four Americans dies of cancer. Cancer is characterized primarily by an increase in the number of abnormal, or neoplastic, cells derived from a given normal tissue which proliferate to form a tumor mass, the invasion of adjacent tissues by these neoplastic tumor cells, and the generation of malignant cells which spread via the blood or lymphatic system to regional lymph nodes and to distant sites. The latter progression to malignancy is referred to as metastasis.
Cancer can be viewed as a breakdown in the communication between tumor cells and their environment, including their normal neighboring cells. Signals, both growth-stimulatory and growth-inhibitory, are routinely exchanged between cells within a tissue. Normally, cells do not divide in the absence of stimulatory signals, and, likewise, will cease dividing in the presence of inhibitory signals. In a cancerous, or neoplastic, state, a cell acquires the ability to xe2x80x9coverridexe2x80x9d these signals and to proliferate under conditions in which normal cells would not grow.
Tumor cells must acquire a number of distinct aberrant traits to proliferate. Reflecting this requirement is the fact that the genomes of certain well-studied tumors carry several different independently altered genes, including activated oncogenes and inactivated tumor suppressor genes. Each of these genetic changes appears to be responsible for imparting some of the traits that, in aggregate, represent the full neoplastic phenotype (Land, H. et al., 1983, Science 222:771; Ruley, H. E., 1983, Nature 304:602; Hunter, T., 1991, Cell 64:249).
In addition to unhindered cell proliferation, cells must acquire several traits for tumor progression to occur. For example, early on in tumor progression, cells must evade the host immune system. Further, as tumor mass increases, the tumor must acquire vasculature to supply nourishment and remove metabolic waste. Additionally, cells must acquire an ability to invade adjacent tissue, and, ultimately, cells often acquire the capacity to metastasize to distant sites.
The biochemical basis for immune recognition of tumor cells is unclear. It is possible that the tumorigenicity of cells can increase when the cells"" display of Class I histocompatability antigens is reduced (Schrier, P. I. et al., 1983, Nature 305:771), in that these antigens, in conjunction with tumor-specific antigens are required for the tumor cells to be recognized by cytotoxic T lymphocytes (CTLs). Tumor cells which have lost one or more genes encoding tumor-specific antigens seem to escape recognition by the corresponding reactive CTLs (Van der Bruggen, P. et al., 1991, Science 254:1643).
Once a tumor reaches more than about 1 mm in diameter, it can no longer rely on passive diffusion for nutrition and removal of metabolic waste. At this point, the tumor mass must make intimate contact with the circulatory system. Thus, cells within more advanced tumors secrete angiogenic factors which promote neovascularization, the growth of blood vessels from surrounding tissue into the tumor mass (Folkman, J. and Klagsburn, M., 1987, Science 235:442; Liotta, L. A. et al., 1991, Cell 64:327). Among these angiogenic factors are the fibroblast growth factor (FGF) and endothelial cell growth factor (ECGF). Neovascularization can, in fact, be an essential precursor to metastasis. First, the process is required for a large increase in tumor cell number, which in turn, allows the appearance of rare metastatic variants. Further, neovascularization provides a direct portal entry into the circulatory system which can be used by metastasizing cells.
A variety of biochemical factors have been associated with different phases of metastases. Cell surface receptors for collagen, glycoproteins such as laminin, or proteoglycans, facilitate tumor cell attachment, an important step in invasion and metastases. Attachment then triggers the release of degradative enzymes which facilitate the penetration of tumor cells through tissue barriers. Once the tumor cell has entered the target tissue, specific growth factors are required for further proliferation.
It is apparent that the complex process of tumor progression must involve multiple gene products. It is therefore important to define the role of specific genes involved in tumor progression, to identify those gene products involved in the tumor progression process and to further identify those gene products which can serve as therapeutic targets for the diagnosis, prevention and treatment of metastases of various forms of cancers.
Some attempts have been made to study genes which are thought to elicit or augment tumor progression phenotypes. Mutations may drive a wave of cellular multiplication associated with gradual increases in tumor size, disorganization and malignancy. For example, a mutation in the tumor suppressor gene which is a negative regulator of cellular proliferation, results in a loss of crucial control over tumor growth and progression. Differential expression of the following suppressor genes has been demonstrated in human cancers: the retinoblastoma gene, RB; the Wilms"" tumor gene, WT1 (11p); the gene deleted in colon carcinoma, DCC (18q); the neurofibromatosis type 1 gene, NF1 (17q); and the gene involved in familial adenomatous polyposis coli, APC (5q) (Vogelstein, B. and Kinzler, K. W., 1993, Trends Genet. 9:138-141).
Insight into the complex events that lead from normal cellular growth to neoplasia, invasion and metastasis is crucial for the development of effective diagnostic and therapeutic strategies. The foregoing studies are aimed at defining the role of particular gene products presumed to be involved in tumor progression. However, such approaches cannot identify the full panoply of gene products that are involved in the cascade of steps in tumor progression. A great need, therefore, exists for the successful identification of those genes which are differentially expressed in cells involved in or predisposed to a tumor progression phenotype. Such differentially expressed gene and/or gene products can represent useful diagnostic markers and/or therapeutic targets for tumor progression disorders. With respect to diagnostic techniques, such genes and/or gene products could represent useful markers for the diagnosis, especially early diagnosis, given the correlation between early diagnosis and successful cancer treatment. With respect to therapeutic treatments, such differentially expressed genes and/or gene products could represent useful targets for therapeutic treatment of various forms of tumor progression disorders, including metastatic and non-metastatic neoplastic disorders, and for inhibiting the progression of pre-neoplastic lesions (e.g., hyperplastic lesions or other benign tumors) to malignant tumors.
Differentially expressed genes involved in tumor metastasis have been identified using murine melanoma cell lines of varying metastatic potentials, N-nitroso-methylurea-induced rat mammary carcinomas, mammary carcinoma cell lines, human breast tumors and spontaneous colonic and intestinal tumors in mice (Steeg, P. S., et al., 1988, J. Natl. Cancer Inst. 80:200-204; Qian, F., et al., 1994, Cell 77:335-347; Leone, A., et al., 1991, 65:25-35; Zou, Z., et al., 1994, Science 263:526-529; and Fodde, R., et al., 1994, Proc. Natl. Acad. Sci. USA 91:8969-8973).
The present invention relates to methods and compositions for diagnosis, prevention, and treatment of tumor progression. Specifically, murine and human genes are identified and described which are differentially expressed in tumor cells relative to normal cells and/or to tumor cells at a different stage of tumor progression. For example, genes are identified which are differentially expressed in benign (e.g., non-malignant) tumor cells relative to malignant, metastatic tumor cells. The modulation of the expression of the identified genes and/or the activity of the identified gene products can be utilized therapeutically to treat disorders involving tumor progression, including, for example, metastatic disorders. As such, methods and compositions are described for the identification of novel therapeutic compounds for the inhibition of tumor progression and the treatment of tumor progression disorders, including metastatic diseases.
Further, the identified genes and/or gene products can be used to identify cells exhibiting or predisposed to a disorder involving a tumor progression phenotype, thereby diagnosing individuals having, or at high risk for developing, such disorders. Additionally, the identified genes and/or gene products can be used to grade or stage identified tumor cells. Still further, the detection of the differential expression of identified genes can be used to devise treatments (for example, chemoprevention) before the benign cells attain a malignant state. Still further, the detection of differential expression of identified genes can be used to design a preventive intervention in pre-neoplastic cells in individuals at high risk.
xe2x80x9cTumor progression,xe2x80x9d as used herein, refers to any event which, first, promotes the transition of a normal, non-neoplastic cell to a cancerous, neoplastic one. Such events include ones which occur prior to the onset of neoplasia, and which predispose, or act as a step toward, the cell becoming neoplastic. These events can, for example, include ones which cause a normal cell to exhibit a pre-neoplastic phenotype. Second, such events also include ones which bring about the transition from a pre-neoplastic state to a neoplastic one. Such events can, for example, include ones which promote two hallmarks of the neoplastic state, namely unhindered cell proliferation and/or tumor cell invasion of adjacent tissue. Third, tumor progression can include events which promote the transition of a tumor cell to a metastatic state. Within each state, (e.g., pre-neoplastic, neoplastic and metastatic) the term xe2x80x9ctumor progressionxe2x80x9d as used herein can also refer to the disorder severity or aggressiveness a cell exhibits relative to other cells within the same state.
Because multiple tumor progression events occur as a cell progresses from normal to neoplastic and metastatic states, certain cells will have undergone a different set of such tumor progression events. As such, such cells are referred to herein as belonging to different xe2x80x9ctumor progression stages.xe2x80x9d
A xe2x80x9cdisorder involving tumor progressionxe2x80x9d or a xe2x80x9ctumor progression disorder,xe2x80x9d as used herein, refers to the state of a cell or cells which have undergone or are in the process of undergoing a tumor progression event, as defined above.
xe2x80x9cDifferential expression,xe2x80x9d as used herein, refers to both quantitative, as well as qualitative, differences in the genes"" temporal and/or cellular expression patterns among, for example, normal and neoplastic tumor cells, and/or among tumor cells which have undergone different tumor progression events. Differentially expressed genes can represent xe2x80x9cfingerprint genes,xe2x80x9d and/or xe2x80x9ctarget genes.xe2x80x9d
xe2x80x9cFingerprint gene,xe2x80x9d as used herein, refers to a differentially expressed gene whose expression pattern can be utilized as part of a prognostic or diagnostic marker for the evaluation of a disorder involving tumor progression, or which, alternatively, can be used in methods for identifying compounds useful for the treatment of such disorders. For example, the effect of the compound on the fingerprint gene expression normally displayed in connection with disorders involving tumor progression can be used to evaluate the efficacy of the compound as a treatment for such a disorder, or can, additionally, be used to monitor patients undergoing clinical evaluation for the treatment of the disorder.
xe2x80x9cFingerprint pattern,xe2x80x9d as used herein, refers to the pattern generated when the expression pattern of a series (which can range from two up to all. the fingerprint genes which exist for a given state) of fingerprint genes is determined. A fingerprint pattern can be used in the same diagnostic, prognostic and compound identification methods as the expression of a single fingerprint gene.
xe2x80x9cTarget gene,xe2x80x9d as used herein, refers to a differentially expressed gene involved in tumor progression such that modulation of the level of target gene expression or of target gene product activity can act to prevent and/or ameliorate symptoms of the tumor progression. Compounds that modulate the expression of the target gene or the activity of the target gene product can be used in the treatment of neoplastic diseases, including, for example, disorders involving the progression to a metastatic state. Still further, compounds that modulate the expression of the target gene or activity of the target gene product can be used in treatments to prevent benign cells from attaining a malignant state. Still further, compounds that modulate the expression of the target gene or activity of the target gene product can be used to design a preventive intervention in pre-neoplastic cells in individuals at high risk.
Further, xe2x80x9cpathway genesxe2x80x9d are defined via the ability of their products to interact with other gene products involved in tumor progression disorders. Pathway genes can also exhibit target gene and/or fingerprint gene characteristics.
The present invention includes the products of such fingerprint, target, and pathway genes, as well as antibodies to such gene products. Furthermore, the engineering and use of cell-based and/or animal-based models of tumor progression disorders, including disorders involving metastasis, to which such gene products can contribute, are described.
The present invention also relates to methods for prognostic and diagnostic evaluation of tumor progression conditions, and for the identification of subjects containing cells predisposed to such conditions. Furthermore, the invention provides methods for evaluating the efficacy of therapies for disorders involving tumor progression, and for monitoring the progress of patients participating in clinical trials for the treatment of such diseases.
The tumor progression disorders described herein can include disorders involved in the progression of such human cancers as, for example, human melanomas, breast, gastrointestinal, such as esophageal, stomach, colon, bowel, colorectal and rectal cancers, prostate, bladder, testicular, ovarian, uterine, cervical, brain, lung, bronchial, larynx, pharynx, liver, pancreatic, thyroid, bone, leukemias, lymphomas, and various types of skin cancers.
The invention also provides methods for the identification of compounds that modulate the expression of genes or the activity of gene products involved in tumor progression, including the progression of metastatic neoplastic diseases, as well as methods for the treatment of such diseases. Such methods can, for example, involve the administration of such compounds to individuals exhibiting symptoms or markers of tumor progression, such as markers for metastatic neoplastic diseases.
This invention is based, in part on systematic search strategies involving in vivo and in vitro paradigms of tumor progression, including the progression to metastatic disease, coupled with sensitive and high throughput gene expression assays, to identify genes differentially expressed in tumor cells relative to normal cells and/or relative to tumor cells at a different tumor progression stage. In contrast to approaches that merely evaluate the expression of a given gene product presumed to play a role in one or another of the various stages of tumor progression, such as, for example the progression to a metastatic disease process, the search strategies and assays used herein permit the identification of all genes, whether known or novel, which are differentially expressed in tumor cells relative to normal cells or relative to tumor cells at a different stage of tumor progression.
This comprehensive approach and evaluation permits the discovery of novel genes and gene products, as well as the identification of an array of genes and gene products (whether novel or known) involved in novel pathways that play a major role in the disease pathology. Thus, the present invention makes possible the identification and characterization of targets useful for prognosis, diagnosis, monitoring, rational drug design, and/or other therapeutic intervention of tumor progression disorders, including disorders involving metastasis.
The Example presented in Section 6, below, demonstrates the successful use of tumor progression search strategies of the invention to identify genes which are differentially expressed within tumor cells relative to tumor cells at a different stage of tumor progression. Specifically, the Example identifies a gene which is differentially expressed in metastatic cell populations relative to benign, non-malignant tumor cells.
This gene, referred to herein as the 030 gene (fomy030 in the mouse and fohy030 in humans), is a novel gene which is expressed at a many-fold higher level in non-metastatic tumor cells relative to its expression in metastatic tumor cells. The gene appears in mice and has the cDNA sequence shown in FIGS. 3A and 3B (SEQ ID NO:2). A homologous gene, referred to herein as the fohy030 gene, appears in humans and has the cDNA sequence shown in FIG. 5 (SEQ ID NO:6). An alternative splice form of the human cDNA has the sequence shown in FIG. 6 (SEQ ID NO:8). Unless stated expressly otherwise, any general reference to the 030 gene hereinafter refers to both the murine (fomy030) and human (fohy030) homologs of this gene.
The identification of the 030 gene and the characterization of its expression in particular stages of metastatic spread provides, therefore, newly identified targets for the diagnosis, prevention, and treatment of tumor progression disorders, including metastatic neoplastic diseases.
Its expression pattern indicates that the 030 gene product acts to inhibit tumor progression. For example, a reduction in the level of 030 gene expression correlates with an increase in a cell""s metastatic potential i.e., a reduction of 030 gene product in tumor cells can induce or predispose a cell to progress to a metastatic state.
Hence, any method which can bring about an increase in the amount of 030 gene product can inhibit or slow the progression to metastasis. In fact, it is possible that the 030 gene product exhibits general tumor inhibition properties.
A cDNA clone of the murine homolog, designated fomy030, is described herein in FIGS. 3A and 3B (SEQ ID NO:2) (nucleotide sequence and amino acid sequence), and was derived from fomy030 mRNA. However, as used herein, fomy030 cDNA refers to any DNA sequence that encodes the amino acid sequence depicted in FIGS. 3A and 3B (SEQ ID NO:3).
A cDNA clone of the human homolog, designated fomy030, is shown in FIG. 5 (SEQ ID NO:6) (nucleotide sequence and amino acid sequence). An alternative splice form of fohy030 is shown in FIG. 6 (SEQ ID NO:8). Both were obtained using the entire mouse fomy030 cDNA as a probe. However, as used herein, fohy030 cDNA refers to any DNA sequence that encodes the amino acid sequences depicted in FIG. 5 (SEQ ID NO:7) and FIG. 6 (SEQ ID NO:9).
xe2x80x9cTumor progression,xe2x80x9d as used herein, refers to any event which, first, promotes the transition of a normal, non-neoplastic cell to a cancerous, neoplastic one. Such events include ones which occur prior to the onset of neoplasia, and which predispose, or act as a step toward, the cell becoming neoplastic. These events can, for example, include ones which cause a normal cell to exhibit a pre-neoplastic phenotype. Second, such events also include ones which bring about the transition from a pre-neoplastic state to a neoplastic one. Such events can, for example, include ones which promote unhindered cell proliferation and/or tumor cell invasion of adjacent tissue, which are viewed as hallmarks of the neoplastic state. Third, tumor progression can include events which promote the transition of a tumor cell to a metastatic state. Within each state, (e.g., pre-neoplastic, neoplastic and metastatic) the term xe2x80x9ctumor progressionxe2x80x9d as used herein can also refer to the disorder severity or aggressiveness a cell exhibits.
Because multiple tumor progression events occur as a cell progresses from a normal to neoplastic and metastatic states, certain cells will have undergone a different set of such tumor progression events. As such, such cells are referred to herein as belonging to different xe2x80x9ctumor progression stages.xe2x80x9d
A xe2x80x9cdisorder involving tumor. progressionxe2x80x9d or a xe2x80x9ctumor progression disorder,xe2x80x9d as used herein, refers to the state of a cell or cells which have undergone or are in the process of undergoing a tumor progression event, as defined above.
xe2x80x9cDifferential expression,xe2x80x9d as used herein, refers to both quantitative, as well as qualitative differences in the genes"" temporal and/or cellular expression patterns among, for example, normal and neoplastic tumor cells, and/or among tumor cells which have undergone different tumor progression events. Differentially expressed genes can represent xe2x80x9cfingerprint genes,xe2x80x9d and/or xe2x80x9ctarget genes.xe2x80x9d
xe2x80x9cFingerprint gene,xe2x80x9d as used herein, refers to a differentially expressed gene whose expression pattern can be utilized as part of a prognostic or diagnostic marker for the evaluation of tumor progression, or which, alternatively, can be used in methods for identifying compounds useful for the treatment of tumor progression. For example, the effect of the compound on the fingerprint gene expression normally displayed in connection with tumor progression can be used to evaluate the efficacy of the compound as a treatment for tumor progression, or can, additionally, be used to monitor patients undergoing clinical evaluation for the treatment of tumor progression.
xe2x80x9cFingerprint pattern,xe2x80x9d as used herein, refers to the pattern generated when the expression pattern of a series (which can range from two up to all the fingerprint genes which exist for a given state) of fingerprint genes is determined. A fingerprint pattern can be used in the same diagnostic, prognostic and compound identification methods as the expression of a single fingerprint gene.
xe2x80x9cTarget gene,xe2x80x9d as used herein, refers to a differentially expressed gene involved in tumor progression such that modulation of the level of target gene expression or of target gene product activity can act to prevent and/or ameliorate symptoms of the tumor progression. Compounds that modulate target gene expression or activity of the target gene product can be used in the treatment of tumor progression and tumor progression disorders, including, for example, disorders involving the progression to a metastatic state.
Further, xe2x80x9cpathway genesxe2x80x9d are defined via the ability of their products to interact with other gene products involved in tumor progression. Pathway genes can also exhibit target gene and/or fingerprint gene characteristics.